Carboxymethyloxysuccinic acid, hereinafter referred to as CMOSA, is a known, highly biodegradable ether tricarboxylic acid which is conveniently prepared from maleic anhydride and glycolic acid as described in U.S. Pat. No. 3,914,297 incorporated herein by reference. CMOSA is unique compared to the most similar, structurally analogous ether polycarboxylic acid, namely, oxydiacetic acid. Thus, CMOSA is a relatively safe substance having known utility as a food acidulant and flavoring material (see U.S. Pat. No. 4,015,023) whereas oxydiacetic acid is a known toxic substance. Accordingly, introduction of a carboxymethyloxysuccinic acid residue into an organic molecule to obtain useful polyfunctionality while at the same time not impairing the biodegradability or safety characteristics of the molecule has become a desirable objective.
It is therefore an object of this invention to provide methods for preparing the anhydrides and acid halides of carboxymethyloxysuccinic acid.
It is also an object of this invention to provide useful novel derivatives of the anhydrides and acid halides of carboxymethyloxysuccinic acid.
These and other objects will become apparent as the description proceeds.
The attainment of the above objects is made possible by the conversion of CMOSA into novel anhydrides and/or acid halides. The anhydride and acid halide products are reacted with selected active hydrogen compounds such as water, hydrogen sulfide, ammonia, amines, alcohols, polyols, carbohydrates, amino acids and the like to produce a variety of useful derivatives of carboxymethyloxysuccinic acid.